1. Field of the Invention
The present invention relates generally to a surgical instrument and a method for treating female urinary incontinence.
2. Description of the Related Art
Urinary incontinence is a significant health concern worldwide. Incontinence may occur when the pelvic floor weakens. There are five basic types of incontinence: stress incontinence, urge incontinence, mixed incontinence, overflow incontinence and functional incontinence. There are a large number of surgical interventions and procedures for addressing incontinence.
A variety of surgical procedure options are currently available to treat incontinence. Depending on age, medical condition, and personal preference, surgical procedures can be used to completely restore continence. One type of procedure, found to be an especially successful treatment option for Stress Urinary Incontinence in both men and women, is a sling procedure.
A sling procedure is a surgical method involving the placement of a sling to stabilize or support the bladder neck or urethra. There are a variety of different sling procedures. Descriptions of different sling procedures are disclosed in U.S. Pat. Nos. 5,112,344; 5,611,515; 5,842,478; 5,860,425; 5,899,909; 6,039,686, 6,042,534 and 6,110,101.
Sling procedures differ in the type of material used for the sling, the method of anchoring the sling material in the body and how the sling material is inserted in the body. The time required for a surgical procedure varies, but is preferably as short as possible. This factor is frequently reported in urology and gynecology literature. See Atherton M. J., et al., A Comparison of Bladder Neck Movement and Elevation After Tension-free Vaginal Tape and Colposuspension, British Journal of Obstetrics and Gynecology, November 2000, Vol. 17, p. 366-1370, Nilsson et al, The Tension-free Vaginal Tape Procedure is Successful in the Majority of Women with Indications for Surgical Treatment of Urinary Stress Incontinence, British Journal of Obstetrics and Gynecology, April 2001, Vol. 108, P. 414-419; and Ulmsten et al., An Ambulatory Surgical Procedure Under Local Anesthesia For Treatment of Female Urinary Incontinence, Int. Urogynecol. J. (1996), v. 7, pps. 81-86.
Although serious complications associated with sling procedures are infrequent, they do occur. Complications include urethral obstruction, development of de novo urge incontinence, hemorrhage, prolonged urinary retention, infection, and damage to surrounding tissue and sling erosion. Infection may occur as a result of exposing contaminants from the vagina during the removal of prior art two piece overlapping sheath assemblies via either suprapubic incisions or groin incisions. A two piece overlapping sheath assembly is disclosed in published U.S. patent application No. 2002/0156487-A1.
Many slings include a protective sheath used during insertion of the sling. After the sling is implanted, the sheath is removed and discarded. The protective sheath is generally constructed of a material that affords visual examination of the implantable sling and that affords smooth passage of the sling assembly through tissue of the patient.
In many cases, the sheath is made of polyethylene. Other materials used to construct the sheath include polypropylene, nylon, polyester or Teflon. The sheath material should be flexible and provide sufficient structural integrity to withstand the various forces exerted on the sheath throughout the sling delivery procedure. Referring to FIG. 14, the sheath 44 is configured to have sufficient flexibility to facilitate user manipulation and adequate structural strength to withstand the various forces applied to the sheath 44 during delivery and/or positioning of the sling assembly. It should also conveniently separate from the sling material after the sling is implanted without materially changing the position of the sling.
The sheath 44 may comprise two elongate, separable sections 86. Portion S of the sheath 44 detachably and telescopically overlap near the middle portion of the sling. During sheath removal, the first section and the second section of the sheath are slid off the sling by pulling each end 86 of the sheath 44 away from the middle portion of the sling assembly. Removal of the sheath 44 causes separation of the overlapping sheath sections, thereby exposing the sling.
The problem with the telescoping configuration of the first and second sections of the sheath 44 is that there has been a tendency for the two telescoping sections to “stick” to one another during the removal process believed to be due to either friction caused by the respective telescoping sections of the sheath or use of a spacer such as a clamp under the urethra. In the latter, the spacer increases the friction between the two sheaths and causes them to stick. That is, the overlapping section of the first and second sections of the sheath is situated at the point of maximum curvature and hence the point of maximum interference/friction.